The present invention relates generally to buckles and belt or strap fasteners and, more particularly, to magnetic fasteners such as magnetic buckles and magnetic strap fasteners. More specifically, although not solely limiting thereto, the present invention also relates to fasteners or buckles for use in or with a brassiere or the like.
Unlike conventional fastener assemblies such as an array of buttons in which a button is fastened and released by inserting it into or removing it from a button hole, magnetic buttons and fasteners are fastened or secured by mutual magnetic attraction between a complementary pair of magnetic fasteners or buttons having complementary or opposite magnetic properties. This unique property of magnetic fasteners means that they can be automatically fastened when a detachable pair is in the proximity of each other. At the same time, coupled magnetic buttons can be separated simply by pulling the fasteners or buttons apart and move them away from each other. Also, unlike conventional fasteners such as button assemblies which have to be fastened and released sequentially, an array of magnetic buttons can be simultaneously fastened or released.
The above distinctive characteristics find magnetic fasteners particularly useful in circumstances in which the fasteners are required to be done and undone with a single hand and within a short time. For example, magnetic fasteners are useful in costumes for artists or performers who need to change frequently on stage. They are also useful for workers who wear work clothes and vests which may be caught by machinery or moving objects. Clothes or work vests with magnetic buttons provide easy escape to save the wearer from being caught and hurt when the clothes or vests are engaged accidentally.
As mentioned above, typical magnetic buttons include a pair of complementary parts which are releasably attachable to each other by magnetic attraction. Each of the detachable parts usually includes a magnetic member in slab or tablet form having a top and a bottom magnetic coupling surfaces with the opposite magnetic poles formed on them. The magnetic coupling surfaces are usually interconnected by a continuous peripheral edge which is usually quite thin for aesthetic and styling consideration. The magnetic slabs or tablets are usually cylindrical in shape with substantially identical top and bottom surfaces.
The magnetic slabs or tablets are generally enclosed in a magnetic permeable housing which are made, for example, of rubber, Nylon, fabrics, plastics (such as ABS or PVC) or synthetic resin. The housing makes decoration to the magnetic fasteners possible by providing a cover of aesthetic design to the magnetic member which usually has a monotonous and dull metallic appearance as well as providing weathering shield to the magnetic material to slow down or retard undesirable rusting. In this regard, the enclosure is preferably water- or air-tight so that even if the magnet member is oxidized, the enclosure still provides a cosmetic cover to hide the rusted surfaces from the outside, thereby making magnetic buttons suitable for applications in which product presentation and appearance are important.
To further enhance the convenience and usefulness of magnetic fasteners, magnetic fasteners are always made with complementary magnetic members having identical shapes and dimensions. As a result of the substantially identical dimensions of the complementary magnetic coupling surfaces on the detachable parts, the parts will come into substantially automatic alignment once they come into contact and no external help is therefore required in general for the initial contact and the subsequent engagement.
In view of the many advantages offered by magnetic buckles, it will be expected that magnetic belt or strap fasteners or buckles should be much more widely used, for example and especially, in applications where the buckles are hard to reach or locate or in applications where the buckles are normally concealed underneath other surfaces during use. One example of such applications is in lingeries or brassieres where the buckles are usually located at the back or at locations which are not conveniently accessible. Another example is for braces in which some of the fasteners are to be fastened to the back of trousers. In these applications, the appearance of the fasteners is usually important as their selection is sometimes considered to be representative or reflective of the taste of the user. Hitherto, magnetic buckles are not as widely used as expected in such applications. One main reason for this is probably because conventional magnetic fasteners buckles are very complex, of a bulky build and are expensive, heavy and un-sightly and sometimes difficult to use. Another reason is the fear of accidental disengagement. More importantly, since magnetic buttons are characterised by engagement by mutual magnetic attraction of the coupling surfaces having opposite or complementary magnetic polarities and since magnetic coupling forces are usually strongest in the direction which is substantially normal or perpendicular to the coupling surfaces, the mutual lateral attraction is relatively week and lateral dislocation of the buttons may occur relatively easily by lateral pulling of the buttons which may cause inadvertent or accidental disengagement of the fasteners when a lateral tension is applied. While it may be possible to retard undesirable lateral movement by providing matted or frictional coupling surfaces, this would usually decrease the ease of self alignment between the coupling surfaces and are therefore is not an attractive option.
Hence, it will be desirable if magnetic buckles having at least some of the aforementioned shortcomings overcome or alleviated can be provided so that light, reliable and simple strap fasteners can be provided. Preferably such strap fasteners should have a low-profile structure which allows decoration to be conveniently and easily added to the buckles to make them more aesthetically pleasingxe2x80x94an important aspect if magnetic buckles are to be widely used in lingerie, fashions or apparel. In addition, a low-profile structure usually alleviates the risks of damages to the covering or adjacent soft materials. Naturally, it is highly desirable if such fasteners can be snap-fitted and easily disengageable as and when desired by the user.
Throughout this specification, the terms fasteners, buckles and buttons are used interchangeably for brevity and succinctness to the extent that is appropriate for the context.
It is therefore an object of the present invention to provide a magnetic strap fastener or buckle which is light, of a simple structure and inexpensive. In addition, the strap fastener or buckle should have a low-profile build so that it can be easily and conveniently concealed under clothes or other surfaces for aesthetic consideration so that such fasteners can be generally used in the manufacture of under-clothings such as brassieres and lingeries. Preferably, in addition to the afore-mentioned requirements, the buckles should be reasonably reliable so that the risks of accidental dis-engagement of the buckles or strap fasteners are minimal. As a minimum, it is the object of the present invention to provide the public with a choice of a new form of magnetic fasteners as described herein.
According to the present invention, there is provided a magnetic buckle or strap fastener including a housing and a magnetic member, said magnetic member includes a first surface of a first magnetic polarity and a second surface of a second and opposite magnetic polarity, the perimeters of said first and said second surfaces are joined by a thin peripheral wall, said housing includes a holder for receiving said magnetic member so that at least one surface of said magnetic member will substantially expose and a strap receiving means extending away from said peripheral wall in a direction which is substantially perpendicular to said peripheral wall.
Preferably, the strap receiving means is substantially equi-distant from both polar surfaces of said magnetic member.
Preferably, the holder includes a base portion and a wall extending upwardly from the perimeter of said base portion, said base portion is adjacent one surface of said magnetic member and said wall is adapted to surround the peripheral wall of said magnetic member.
Preferably the wall discontinues at about the junction between said strap receiving means and said base portion.
Preferably, the holder includes a wall surrounding the peripheral wall of said magnetic member, said wall includes an elevated portion protruding beyond the exposed magnetic surface.
Preferably, the elevated portion is adapted so that when said strap fastener is magnetically coupled with a counter-part strap fastener of the same design, said elevated portion will not push against the strap receiving means of the counter-part fastener while forming a barrier member to stop relative lateral movement along the directions of the strap receiving means.
According to another aspect of the present invention, there is provided a strap fastener or a buckle including a housing and a magnetic member, said magnetic member includes a first and a second magnetic polar surfaces respectively of a first and a second magnetic polarities which together define a magnetic axis, said housing includes a receptacle for receiving said magnetic member and a strap receiving means, said strap receiving means is formed on said receptacle and is transverse to said magnetic axis.
Preferably, the strap fastener further including a projection which is disposed on the edge of said receptacle at a position which is substantially opposite to said strap receiving means and which extends beyond the magnetic polar surface which is adapted for coupling with a counterpart magnetic coupling surface.
According to yet another aspect of the present invention, there is provided a buckle or strap fastener comprising a pair of engageable magnetic fasteners of opposite polarity to each other engageable or a common axis and a strap engagement portion connected to each magnetic fastener and extending transverse to said common axis of engagement of said magnetic fasteners. Preferably, said fastener includes at least one protrusion to reside against a perimeter of an opposed magnetic fastener to resist movement of one magnetic fastener with respect to the other transverse to said common axis on which they engage.